Genetic diversity for mineral accumulation in the foliage of Chenopodium spp.

Chenopodium spp. is being used as a leafy vegetable and subsidiary grain crop in different parts of the world due to its rich nutritional quality and its ability to grow in stress conditions. A field experiment was conducted in Lucknow (India) to assess the genetic diversity in 40 accessions of Chenopodium spp. based on mineral composition of the leaves. Principal Component Analysis (PCA) showed that the first 4 PCs (Principal Component) accounted for 74.70% of the total variance among the accessions. The first PC (PC1) accounted for 41.96% of the total qualitative variation and had nickel, zinc and chromium with high positive and copper with high negative coefficients. The most important loadings for PC2 were calcium and potassium. Cluster analysis grouped the accessions into 4 major clusters. The first cluster, which showed maximum diversity, had 17 accessions, all of C. quinoa having high content of most of the heavy metals viz. zinc, chromium, nickel and cadmium. Cluster II was the largest consisting of 18 accessions which had low content of nickel, cadmium and chromium. Cluster III contained 3 accessions that had lowest amount of calcium, iron, magnesium and zinc, while accessions in cluster IV were characterized by high levels of calcium, sodium, magnesium, nickel, chromium and cadmium. Significant genotypic differences existed in the heavy metal uptake by plants. Mineral uptake and concentration in Chenopodium spp. corresponds to the taxonomic categorization in the genus and could also be utilized as a supplementary taxonomic tool for grouping together of closely related taxa. Conclusively the diversity can be exploited in plant breeding programs for increasing nutritional value and for bioremediation purposes.